H2-H3 相变可逆性对高能锂离子电池富镍层状氧化物阴极的影响

Chen Jie, Yang Huiping, Li Tianhao, Liu Chaoyang, Tong Hui, Chen Jiaxin, Liu Zengsheng, Xia Lingfeng, Chen Zhaoyong, Duan Junfei, Li Lingjun

School of Materials Science and Engineering, Changsha University of Science and Technology, Changsha, China.

School of Metallurgy and Environment, Central South University, Changsha, China.

Front Chem. 2019 Jul 16;7:500. doi: 10.3389/fchem.2019.00500. eCollection 2019.

Although LiNiCoMnO is attracting increasing attention on account of its high specific capacity, the moderate cycle lifetime still hinders its large-scale commercialization applications. Herein, the Ti-doped LiNiCoMnO compounds are successfully synthesized. The Li(NiCoMn)TiO sample exhibits the best electrochemical performance. Under the voltage range of 2.74.3 V, it maintains a reversible capacity of 151.01 mAh·g with the capacity retention of 83.98% after 200 cycles at 1 C. Electrochemical impedance spectroscopy (EIS) and differential capacity profiles during prolonged cycling demonstrate that the Ti doping could enhance both the abilities of electronic transition and Li ion diffusion. More importantly, Ti doping can also improve the reversibility of the H2-H3 phase transitions during charge-discharge cycles, thus improving the electrochemical performance of Ni-rich cathodes.

尽管LiNiCoMnO因其高比容量而受到越来越多的关注，但其适中的循环寿命仍然阻碍了其大规模商业化应用。在此，成功合成了Ti掺杂的LiNiCoMnO化合物。Li(NiCoMn)TiO样品表现出最佳的电化学性能。在2.7 - 4.3 V的电压范围内，它在1 C下循环200次后保持151.01 mAh·g的可逆容量，容量保持率为83.98%。电化学阻抗谱（EIS）和长时间循环过程中的微分容量曲线表明，Ti掺杂可以增强电子转移和锂离子扩散能力。更重要的是，Ti掺杂还可以改善充放电循环过程中H2 - H3相变的可逆性，从而提高富镍正极的电化学性能。